July 15, 2010
09:00 AM (EDT)

News Release Number: STScI-2010-21

Superhot Planet Likely Possesses Comet-like Tail

July 15, 2010: As if the debate over what is and what is not a planet hasn't gotten
confusing enough, Hubble Space Telescope astronomers have now
confirmed the existence of a tortured, baked object that could be
called a "cometary planet." The gas giant planet, dubbed HD 209458b, is orbiting so close to its
star that its heated atmosphere is escaping away into space. Now, observations by the new Cosmic Origins Spectrograph (COS) aboard
NASA's Hubble suggest that powerful stellar winds are sweeping the
castoff material behind the scorched planet and shaping it into a
comet-like tail.

This artist's illustration shows a view of HD 209458b, as seen from the
surface of a hypothetical nearby companion object.